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Quantum communication is a secure way to transfer quantum information and to communicate with legitimate parties over distant places in a network. Although communication over a long distance has already been attained, technical problem…

Quantum Physics · Physics 2019-03-07 Bikash K. Behera , Swarnadeep Seth , Antariksha Das , Prasanta K. Panigrahi

An m-uniform quantum state on n qubits is an entangled state in which every m-qubit subsystem is maximally mixed. Starting with an m-uniform state realized as the graph state associated with an m-regular graph, and a classical [n,k,d \ge…

Quantum Physics · Physics 2025-10-10 Sowrabh Sudevan , Sourin Das , Thamadathil Aswanth , Nupur Patanker , Navin Kashyap

Entanglement purification protocols are fundamental primitives in quantum communication, enabling the distillation of high-quality entanglement using only local operations and classical communication. For large multipartite states, however,…

Quantum Physics · Physics 2026-04-06 Katerina Stloukalova , Jorge Miguel-Ramiro , Wolfgang Dür , Julius Wallnöfer

Entanglement is crucial for quantum networks and computation, yet maintaining high-fidelity entangled quantum states is hindered by decoherence and resource-intensive purification methods. Here, we experimentally demonstrate entanglement…

In this work, we present a novel authenticated Quantum Key Distribution (QKD) protocol employing maximally entangled qubit pairs. In the absence of noise, we securely authenticate the well-known BB84 QKD scheme under two assumptions: first,…

Quantum Physics · Physics 2025-10-22 Pol Julià Farré , Vladlen Galetsky , Soham Ghosh , Janis Nötzel , Christian Deppe

Quantum error correcting (QEC) codes protect quantum information against environmental noise. Computational errors caused by the environment change the quantum state within the qubit subspace, whereas quantum erasures correspond to the loss…

Quantum Physics · Physics 2025-11-26 Luis Colmenarez , Seyong Kim , Markus Müller

Quantum entanglement distillation protocols are LOCC protocols between Alice and Bob that convert imperfect EPR pairs, or, in general, partially entangled bipartite states into perfect or near-perfect EPR pairs. The classical communication…

Quantum Physics · Physics 2007-05-23 Andris Ambainis , Ke Yang

In this work, we consider decoupling a bipartite quantum state via a general quantum channel. We propose a joint state-channel decoupling approach to obtain a one-shot error exponent bound without smoothing, in which trace distance is used…

Quantum Physics · Physics 2024-09-24 Hao-Chung Cheng , Frédéric Dupuis , Li Gao

The entanglement resource required for quantum information processing comes in a variety of forms, from Bell states to multipartite GHZ states or cluster states. Purifying these resources after their imperfect generation is an indispensable…

Quantum Physics · Physics 2021-09-09 Stefan Krastanov , Alexander Sanchez de la Cerda , Prineha Narang

Open system quantum dynamics can generate a variety of long-range entangled mixed states, yet it has been unclear in what sense they constitute phases of matter. To establish that two mixed states are in the same phase, as defined by their…

Quantum Physics · Physics 2026-02-27 Shengqi Sang , Yijian Zou , Timothy H. Hsieh

We introduce a new protocol, the channel-state coding protocol, to quantum Shannon theory. This protocol generates entanglement between a sender and receiver by coding for a noisy quantum channel with the aid of a noisy shared state. The…

Quantum Physics · Physics 2010-08-12 Mark M. Wilde , Min-Hsiu Hsieh

Distilling high-dimensional quantum entanglement under realistic, general asymmetric noise remains a formidable challenge. Standard entanglement purification protocols inevitably fail to satisfy convergence constraints under severe…

Quantum Physics · Physics 2026-05-26 Zihua Song , Lin Chen , Yongge Wang

Quantum error correction is fundamentally important for quantum information processing and computation. Quantum error correction codes have been studied and constructed since the pioneering papers of Shor and Steane. Optimal (called MDS)…

Quantum Physics · Physics 2022-08-01 Hao Chen

Noise is the main obstacle for the realization of fault tolerant quantum information processing and secure communication over long distances. In this work, we propose a communication protocol relying on simple linear optics that optimally…

Quantum Physics · Physics 2015-06-16 Mikael Lassen , Adriano Berni , Lars S. Madsen , Radim Filip , Ulrik L. Andersen

Nonclassical correlations between the quadrature-phase amplitudes of two spatially separated optical beams are exploited to realize a two-channel quantum communication experiment with a high degree of immunity to interception. For this…

Quantum Physics · Physics 2009-11-06 S. F. Pereira , Z. Y. Ou , H. J. Kimble

To realize the Quantum Internet, quantum communications require pre-shared entanglement among quantum nodes. However, both the generation and the distribution of the maximally-entangled quantum states are inherently contaminated by quantum…

Quantum Physics · Physics 2021-10-22 Daryus Chandra , Angela Sara Cacciapuoti , Marcello Caleffi , Lajos Hanzo

Probabilistic error cancellation (PEC) is unbiased but suffers exponential sampling overhead set by noise-weighted circuit volume, whereas quantum error-detecting codes (QEDCs) remove many physical faults by stabilizer post-selection but…

Quantum Physics · Physics 2026-05-13 Yi Yuan , Yuanchen Zhao , Dong E. Liu

We study the equivalence between a realistic quantum key distribution protocol using coherent states and homodyne detection and a formal entanglement purification protocol. Maximally-entangled qubit pairs that one can extract in the formal…

Quantum Physics · Physics 2007-05-23 G. Van Assche , S. Iblisdir , N. J. Cerf

We find the necessary and sufficient condition under which two two-qubit mixed states can be purified into a pure maximally entangled state by local operations and classical communication. The optimal protocol for such transformation is…

Quantum Physics · Physics 2007-05-23 Enric Jane

Dense coding is the seminal example of how entanglement can boost qubit communication, from sending one bit to sending two bits. This is made possible by projecting separate particles onto a maximally entangled basis. We investigate more…